Pressure-Engineered Through-Space Conjugation for Precise Control of Clusteroluminescence.

Clusteroluminogens (CLgens) represent an innovative class of nonconjugated luminophores that address the limitations of conventional π-conjugated molecules. Different from the through-bond conjugation mechanism in π-conjugated luminophores, through-space conjugation (TSC) plays dominant roles in CLgens. However, precisely controlling TSC to customize the optical properties of CLgens remains a significant challenge. This work proposes a novel strategy of high pressure to engineer TSC within tetraphenylalkanes (TPAs)-based CLgens at molecular level. High-pressure exploration enables accurate manipulation of clusteroluminescence and elucidates the intrinsic structure-property relationships involved. Upon initial compression, the predominant molecular distortions marked by increased interfacial angles between benzene rings diminish TSC, resulting in anomalous hypochromatic shift in emission. Subsequently, considerable structural contraction enhances TSC and suppresses molecular motion, resulting in a pronouncedly enhanced and bathochromic-shifted emission. Notably, a series of TPAs-based CLgens exhibit intense white-light emission upon pressure release, attributed to irreversible structural distortion and destruction. This study not only advances the understanding of CLgens, but also underscores the crucial structural factors for effective TSC control, paving the way for establishing new photophysical theories for aggregate science.